This invention relates to fluid handling, and more particularly to remotely activated dispensing of chemical solutions from a dispenser.
Systems for dispensing chemical solutions often mix the solutions as needed by adding a concentrated chemical product to a diluent such as water. One type of dispenser uses a mixing device known as an eductor. Eductors siphon the concentrated chemical product into a stream of diluent by passing the diluent through a venturi. In response to diluent flowing through the eductor, the venturi generates suction that draws the concentrated chemical product into the venturi where it mixes with the stream of diluent. The resulting solution flowing out of the eductor may then be dispensed into a container or otherwise provided to a point of use. The mixing and dispensing of the chemical solution is controlled by regulating the flow of diluent through the eductor with a user controlled shut-off valve. Eductors are useful in a number of applications where it is advantageous to allow users to dispense desired amounts of chemical solutions such as diluted cleaning agents.
Eductor-based chemical dispensing systems are typically required to prevent chemical products from being drawn back into the source of diluent to prevent contamination. This is often accomplished by coupling the inlet port of the eductor to the source of diluent using some type of backflow preventer. For example, in what is known as an air gap eductor, the source of diluent flows through a nozzle upstream of the venturi. This nozzle defines a stream of diluent which flows across an unobstructed gap in the eductor body prior to entering the venturi. If there is a loss of pressure at the source of diluent, the stream of diluent terminates, leaving a gap in the eductor between the nozzle and the venturi. This gap prevents any of the chemical product from back-flowing into the source of diluent. Whichever type of backflow preventer is used, the diluent shut-off valve typically must be located upstream of the backflow preventer so the backflow preventer functions properly, and to satisfy regulatory requirements regarding contamination of the diluent source.
Solutions provided by the eductor are typically transported to the point of use through a discharge tube. Because the shut-off valve that controls the dispensing of solutions must be located upstream of the dispenser, and the output end of the discharge tube may be at another location some distance from the dispenser, a system for remotely activating the shut-off valve is normally provided at the output end of the discharge tube. Conventional remote activation systems include a lever located at the output end of the discharge tube that is coupled to the shut-off valve through a system of cables and/or ball chains. However, these systems suffer from various issues such as wear and binding that limit their performance and reliability.
Thus, there is a need for improved devices and methods for remotely actuating shut-off valves in dispensing systems using eductors that provide more reliable and consistent operation of the shut-off valve.